Conventional portable breathing devices are known which range from emergency breathing apparatuses to nebulizers for delivering inhalated aerosolized medications. For instance, Orr (U.S. Pat. No. 5,979,442) discloses an emergency breathing apparatus having a mouthpiece attached to an oxygen container, and includes a decorative front portion attachable to the oxygen container. Williamson (U.S. Pat. No. 4,996,982) discloses a portable emergency breathing apparatus with a mouthpiece, regulator, air storage container, and a holster for storing the apparatus when not in use. Pruitt (U.S. Pat. No. 5,653,223) adapts a nebulizer to a standard oxygen delivery tank to deliver metered quantities of nebulized liquid medication.
In general, the conventional breathing devices suffer from limitations unique to small portable applications. In many instances, the known breathing devices utilize potentially hazardous chemicals. For example, several chemical systems have been developed, mainly for commercial aircraft use, that create oxygen via an exothermic reaction. The exothermic reaction couples with a reaction in which sodium chlorate is decomposed to oxygen and sodium chloride. These systems can be inadvertently activated by mechanical agitation, and also require very high temperatures for the decomposition reaction.
In other instances, the conventional breathing devices suffer from complicated constructions requiring, for instance, adapters, connectors, reagent chambers, masks, and metering mechanisms for powdered or liquid medications for mixing with oxygen or ambient air. In particular, many conventional breathing devices, designed to supply oxygen, require separate oxygen accumulator chambers located apart from their regulators. Such devices are suitable for stationary settings such as in aircraft or hospitals but are cumbersome in dynamic settings.